Device for stopping a working element in a given position

ABSTRACT

A device for stopping a working element in a given position. For example, in the case of a sewing machine, the working element is a needle which should always be located in a given position displaced out of the work when the machine stops operating. The device includes a high-speed drive operatively connected with the working element to drive the latter at a relatively high speed during normal operation of the machine. In addition there is a low-speed drive connected with the working element to drive the latter at a relatively low speed, and the operator of the machine can switch over from the high-speed drive to the low-speed drive in preparation for stopping the operation of the machine. A blocking component coacts with the low-speed drive for blocking the transmission of power therefrom to the working element as soon as the latter reaches a given position so that the working element will remain in this latter position. Because the termination of the drive to the working element and the location thereof in the predetermined stopped position takes place only when driving through the low-speed drive, the stressing of the machine components is reduced and the smoothness of the entire stopping operation is enhanced.

United States Patent [72] Inventor Joseph Chudner 2907 Brighton 8th St.,Brooklyn, N.Y. 11235 {21] Appl. No. 802,806 [22] Filed Feb. 27, 1969[45] Patented June 22, 1971 [54] DEVICE FOR STOPPING A WORKING ELEMENTIN A GIVEN POSITION 11 Claims, 10 Drawing Figs.

[52] US. Cl. 112/219, 192/99,192/3.5, 74/512 [51] Int. Cl D05b 69/22[50] FieldofSearch 112/219,

[56] References Cited UNITED STATES PATENTS 2,332,649 10/1943 Kott112/219 X 1,926,604 9/1933 Terry... 112/219 2,159,722 5/1939 Bedard112/219 (A) 2,936,727 5/1960 Ashworth et al 1 12/219 PrimaryExaminer-41. Hampton Hunter At!orneyBlum, Moscovitz, Friedman and KaplanABSTRACT: A device for stopping a working element in a given position.For example, in the case of a sewing machine, the working element is aneedle which should always be located in a given position displaced outof the work when the machine stops operating. The device includes ahigh-speed drive operatively connected with the working element to drivethe latter at a relatively high speed during normal operation of themachine. In addition there is a low-speed drive connected with theworking element to drive the latter at a relatively low speed, and theoperator of the machine can switch over from the high-speed drive to thelow-speed drive in preparation for stopping the operation of themachine. A blocking component coacts with the low-speed drive forblocking the transmission of power therefrom to the working element assoon as the latter reaches a given position so that the working elementwill remain in this latter position. Because the termination of thedrive to the working element and the location thereof in thepredetermined stopped position takes place only when driving through thelow-speed drive, the stressing of the machine components is reduced andthe smoothness of the entire stopping operation is enhanced.

PATENTEuJuuzmm: 3,585,949

sum 3 0F 4 ATTORNEYS DEVICE FOR STOPPING A WORKING ELEMENT IN A GIVENPOSITION CROSS REFERENCE TO RELATED APPLICATION The present applicationdiscloses further developments of devices of the type shown in copendingapplication Ser. No. 681,470, filed Nov. 8, 1967 and entitled STRUCTUREFOR STOPPING A MACHINE IN A GIVEN POSITION now US. Pat. No. 3,534,845,dated Oct. 20, 1970.

BACKGROUND OF THE INVENTION The present invention relates to devices forstopping the working element of a machine in a given position.

Thus, the present invention is applicable, for example, to sewingmachines in order to situate the needle thereof in a predeterminedposition out of the work when the operation of the machine isterminated.

There are various known ways of locating such a working element at agiven location when the operation thereof is terminated. Thus, it isvery well-known that with sewing machines the operator can simplymanually turn a flywheel or the like until the needle is located at apreselected position. In addition, there are automatic devices whichoperate to terminate the movement of a working element when the latterhas reached a given position. However, structures of this latter typehave certain drawbacks. For example, it is possible to use brakes tostop the operations, but such devices do not operate smoothly and oftengrab or seize so as to provide a sudden impact-type of termination ofthe movement of the machine components. The result is very greatstressing of the components and sudden terminations of movementresulting in loud banging and jerky operation with parts rapidlybecoming worn and loose so that considerable maintenance is required.

SUMMARY OF THE INVENTION It is accordingly a primary object of thepresent invention to provide a construction which will avoid the abovedrawbacks.

In particular, it is an object of the invention to provide aconstruction which will enable a machine element to be stopped in agiven position with a smooth impact-free type of operation.

Thus, in the specific case of the needle of a sewing machine, it is anobject of the invention to provide a construction capable of stoppingthe needle at a location where it is out of the work while at the sametime bringing the operating parts of the sewing machine gradually andsmoothly to a stop.

Also, it is an object of the invention to provide an assembly which willaccomplish the above objects and which can be attached very convenientlyand inexpensively to existing structures.

In addition it is an object of the invention to provide a constructionof this type which is relatively simple and inexpensive to manufactureand which requires minimum maintenance once it is set up for operation.

According to the invention a high-speed drive means transmits a drive toa working element of a machine so as to drive the working element duringnormal operations. A low-speed drive means is also provided for coactionwith the working element to drive the latter at a relatively low speedin preparation for stopping the operation of the working element. Ameans is provided for enabling the operator to switch over from thehighspeed to the low-speed drive means preparatory to stopping theoperation of the working element. In addition, a blocking means coactswith the low-speed drive means to terminate transmission of a drivetherefrom to the working element when the latter has reached thepredetermined given position at which it is to be stopped.

BRIEF DESCRIPTION OF DRAWINGS The invention is illustrated by way ofexample in the accompanying drawings which form part of this applicationand in which:

FIG. I is a simplified perspective view of a sewing machine providedwith structure of the invention;

FIG. 2 shows the structure of FIG. 1 in a side elevation as it appearsfrom the right of FIG. 1;

FIG. 3 is a sectional plan view of the structure of the invention takenalong line 3-3 of FIG. 2 in direction of the arrows and showing thestructure at a scale larger than that of FIG. 2;

FIG. 4 is a sectional elevation of the structure of FIGS. 2 and 3 takenalong line 4-4 of FIG. 3 in the direction of the arrows;

FIG. 5 shows the structure of FIG. 4 in a position taken by the partsduring operation;

FIG. 6 is a longitudinal sectional elevation of the structure takenalong line 6-6 of FIG. 5 in the direction of the arrows;

FIG. 7 is a fragmentary elevation at a scale larger than FIG. I showingthe manner in which treadle operation is used to control the drive froma motor;

FIG. 8 is a longitudinal section elevation taken along line 8-8 of FIG.7 in the direction of the arrows and showing further details of thestructure of FIG. 7;

FIG. 9 is a longitudinal sectional elevation taken along line 9-9 ofFIG. 1 in the direction of the arrows and showing, at an enlarged scaleas compared to FIG. 1, part of the transmission from the treadle to thecontrols of the structure of the invention; and

FIG. 10 is a diagrammatic representation of the needle of the sewingmachine.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to the drawings,FIGS. 1 and 2 show a suitable table 12 which carries the sewing machinestructure as well as the structure of the invention and at which theoperator is seated during sewing operations. The table includes the legs14 as well as the table top 16. Between the legs 14 there is a baseplate18 formed with suitable openings to provide an adjustable location forthe treadle 20. This treadle 20 has at its ends coaxial pivot pinsreceived in bearing openings of ears 22 so that in this way the treadle20 is supported for swinging movement. During operations the operatorwill with a toe portion of a foot move the inner end 24 of the pedal 20downwardly in order to start the operation of the machine. To stop theoperation the operator will, with a heel portion of a foot, move thefront or outer end 26 of the pedal downwardly so as to stop theoperation of the machine.

The machine table 12 has fixed to the underside of the tabletop I6 amain driving motor 28 which is turned on by a master switch 31 alsofixed to the underside of the tabletop I6. Whenever this switch isclosed the electric motor 28 operates. Referring to FIG. 7, as well asFIG. 1, the motor 28 includes in a well-known way, in its interior, abrake which releases the drive from the motor when the brake isdisengaged or which prevents the motor from transmitting a drive whenthe brake is engaged. This known brake assembly is operated by aswinglever 30 having a U-shaped end portion 32 pivoted to the motor asby pivot bolts 34. The lower horizontal arm of the swing-lever 30 isprovided with a series of openings 36. Also, the lever 30 carries acontrol rod 38 passing freely through an opening of a plate 40 which isfixed to the housing of the motor 28. On the left side of the plate 40,as viewed in FIG. 7, the rod 38 carries a coil spring 42 against which awingnut 44 presses so as to control the compression of the coil spring42, the rod 38 being suitably threaded to receive the nut 44 as well asa nut 46 at its opposite end where it extends through an opening of thelever 30. The compression of the spring 42 is such that it tends todisplace the rod 38 to the left, as viewed in FIG. 7, thus swinging thelever 30 in a clockwise direction to locate the brake of the motor 28 inthe position where it prevents transmission of the drive to themotor-driven pulley 48.

As may be seen from FIG. 8, a bolt 50 extends through one of theopenings 36 of the lever 30 and is fixed in position by a nut 52. Thebolt passes through an opening of a plate 54 having at its left end, asviewed in FIG. 7, rearwardly directed ears overlapping the upper andlower edges of the lever 30 and having setscrews 56 threaded throughbores of these ears and engaging the upper and lower edges of the lever30 to center the plate 54 on the lever 30 particularly in the case wherethe latter has a width which is less than the distance between the earswhich carry the screws 56. The plate 54 is itself provided in its cornerregions with threaded bores which receive screws 58 which pass throughopenings of a guide plate 60 having at its right and left edges asviewed in FIG. 7, flanges engaging the front surface of lever 30 visiblein FIG. 7. Thus, the plate 60 is of a substantially U-shaped crosssection and forms a guide for an elongated bar 62. This bar 62 can befixed at any selected elevation by tightening of a setscrew 64 whichpasses into a threaded bore formed centrally in the guide plate 60 at acentral boss thereof.

The elongated bar 62 has a widened upper end portion 66 giving the bar asubstantially T-shaped configuration as is apparent from FIG. 7.

A lever 68 is pivoted at 70 to the upper right corner portion of thewidened end 66 of the bar 62, as viewed in FIG. 7. For example, thisupper portion of the bar is formed with a longitudinal notch having atop open end and receiving the right elongated portion of the lever 68,as viewed in FIG. 7, and this longitudinal notch or groove which isaccessible through the top end of the bar is also formed with atransverse notch or groove 72 of a substantially curved configuration incross section so as to receive part of a roller 74 freely turnable on apin 76 forming part of a bolt which extends through an opening of thelever 68 in the manner shown in FIG. 8.

When the parts are in the position of rest with the transmission fromthe motor 28 to the pulley 48 interrupted, the roller 74 engages theunderside of the motor housing and the lower end of the bar 62 islocated at the elevation of the line 78 (FIG. 7). This is the rest orneutral position of the parts. The left free end portion of the lever63, which is inclined downwardly toward the left, as viewed in FIG. 7,is pivotally connected through suitable fittings to the top end of anelongated rod 80, the bottom end of which is pivoted to a rearwardlydirected ear of an elongated bar 82 fixed to the rear end 24 of thetreadle 20. Thus, when the rear or inner end 24 of the treadle is moveddown, the parts will assume the solid line position indicated in FIG. 7where the drive from the motor 28 to the pulley 46 is released, and atthis time the pulley 48 will rotate. However, it is also possible forthe operator to displace therod 80 upwardly, when depressing the forwardportion 26 of the treadle 20, and now the lever 68 will rock about thepin 76 while the roller 74 remains in engagement with the motor housing,so that the pivot 70 will move down and displace the bar 62 downwardly.In this way the parts will again assume the position shown in FIG. 7except that now the rod 60 and the lever 68 together with the roller 74have the dot-dash line position as shown in FIG. 7. When the drive fromthe motor 28 to the pulley 48 is released so that the pulley 48 isdriven the bar 62 has its lower end situated at the elevation of theline 84 shown in FIG. 7, so that irrespective of whether the rod 80 ismoved up or down, the bar 62 will be displaced from the neutral positionwhere the bottom end of the bar is at the elevation of the line 78 tothe operating position where the bottom end of the bar is at theelevation of the line 84 shown in FIG. 7. In this way operation of thetreadle 20 in either direction will result in displacement of the swinglever 30 in the same direction to release the brake so that the drive istransmitted from the motor 28 to the pulley 48. When the operator doesnot depress either the inner rear edge 24 or the front edge 26 of thetreadle 20, the spring 42 acts to maintain the parts in the neutralposition where the drive from the motor 28 to the pulley 48 isinterrupted.

The pulley 48 drives an endless belt 86 which extends up freely though aslot 88 formed in the tabletop 16 (FIG. 3 and 6). This pulley belt 86passes around a pulley 90 which forms an input transmission element ofhigh and low-speed drive transmissions described below, so that both ofthese latter transmissions have the input element 90 in common. As maybe seen from FIG. 6 in particular, the pulley is fixed to a free end ofa rotary hollow shaft 92 which extends into a housing 94 of the unit ofthe invention and is supported for rotation by any suitable bearingscarried by the end wall 96 and the intermediate wall 98 of the housing94. In order to prevent axial displacement of the hollow shaft 92 acollar 100 is fixed thereto in the interior of the housing 94 engagingthe inner surface of the wall 96.

The left side portion of the pulley 90, as viewed in FIG. 6, forms acomponent 102 of a slip clutch 104. This slip clutch includes a secondcomponent 106 which is fixed to the right side end face, as viewed inFIG. 6, of a pulley I08 which is fixed to a rotary shaft Ill) whichextends slidably through the hollow shaft 92 so as to be freely turnabletherein while supported thereby for rotary movement. This pulley 108forms an output member of the high-speed drive means of the invention aswell as of the low-speed drive means of the invention so that both ofthese drive means have the common input transmission element 90 and thecommon output transmission element 108. The inner surface of thebelt-receiving groove of the pulley MP8 is suitably toothed so as tocoact with the inner teeth of an endless transmission belt 1112 as shownin FIG. 2 extending up to a driving pulley of the operating head of thesewing machine. This operating head is of a conventional constructionknown in the art and not forming any part of the present invention.Through the operating head the needle I16 (FIG. 10) which forms theworking element is reciprocated between the solid and dot-dash linepositions shown in FIG. E0, the parts coacting with a looper 118 in amanner wellknown in the art. When the operations are stopped the needle1116 should be located out of the work 1120 in the solid line positionshown in FIG. 10.

The high-speed drive means of the invention includes only the inputtransmission element 90, the output transmission element 108, and thetransmission therebetween which is formed by the slip clutch 11045. Whenthis clutch is engaged, the drive is transmitted directly from inputelement 90 through clutch 1104 to the output element 108 and then fromthe latter through the belt M2 to the machine. This is the transmissionwhich operates during normal operation of the machine and it operatesthe machine at a relatively high speed on the order of 2800 rpm. forexample. Of course, this speed can be regulated with suitable depressionof the treadle as is well known. Thus if the operator depresses theinner edge 24 to a greater extent the speed is increased while if theinner end 24 of the treadle is depressed to a lesser extent the speedwill be diminished, but during normal operations a relatively high speedis provided for the machine.

The low-speed drive means includes a pulley 1114 also fixed to the shaft92 for rotation therewith, this pulley 1M being coaxial with the pulley90 but of a substantially smaller diameter. The pulley llM drives a belt116 which extends around a pulley 1118 of relatively large diameter, asis apparent from FIG. 3. This pulley 1118 is fixed to the outer end ofthe elongated shaft ll20 also supported for rotary movement by suitablebearings carried by the housing 94. The shaft I20 fixedly carries at itsinner end, adjacent to the removable end wall 122 of the housing 94, apulley 124 (FIGS. 3 and 5). The wall 326 of the housing 94 is formedwith a suitable opening to provide clearance for the pulley 124. Thispulley 126, which is of a substantially smaller diameter than the pulley118, drives an endless belt 128 which extends around a pulley 130 whichis freely turnable on the right end of the shaft 110, as viewed in FIG.6. This pulley 130 carries at its left surface, as viewed in FIG. 6, alayer of a friction material 132 so that this assembly forms part of asecond slip clutch 134. This second slip clutch I34 includes a secondcomponent 1136 in the form of a disc fixed to the shaft llllO forrotation therewith and carrying a positioning pin 138 which rotates withthe disc 136 for a purpose described below. A coil spring M0 surroundsthe part of the shaft Ill!) extending between the wall 98 and the discI36 and pressing against the wall 98 and the disc I36 so as to urgeshaft ill) to the right, as viewed in FIG. 6. In this way the spring 140acts to maintain the slip clutch 104 engaged so that normally thehighspeed drive means will act to operate the needle 116. However, thecomponents formed by the pulleys 114, 118, 124, and 130 form togetherwith the slip clutch 134 part of a stepdown transmission for driving theshaft 110 at a much slower speed, as will be apparent from thedescription which follows.

As is apparent from FIG. 6, the pulley 130 is fixed to a sleeve 142which extends slidably through an opening in the removable wall 122 ofthe housing 94 and which is slidable on the right end of the shaft 110,as viewed in FIG. 6. A small spring washer 144, which is not essential,is situated between elements 130 and 136 to lightly displace element 130away from element 136 so as to maintain the clutch 134 disengaged. Theouter end of the sleeve 142 is closed by an end wall 146 situated nextto the inner end of a threaded stud 148 which extends through a threadedbore formed at the upper end of the rock lever 150 supported forswinging movement on a pin 152 which extends between a pair of ears 154fixed to and projecting from the outer surface of the removable closurewall 122 of the housing 94. The top surface of the bottom wall 156 ofthe housing 94 is suitably grooved, as shown in FIG. 6, to accommodatethe rock lever 150 for swinging movement about the pin 152. The rocklever 150 can be turned from the position shown in FIG. 6 in acounterclockwise direction around the pin 152, as viewed in FIG. 6, soas to press the left end of the screw 148, as viewed in FIG. 6, againstthe sleeve 142 to displace the pulley 130 to the left, as viewed in FIG.6, along the shaft 110. The result is not only that the clutch 134 willbecome engaged, but also that the entire shaft 110 will be displacedslightly to the left, as viewed in FIG. 6, to a distance sufficient todisengage the clutch 104. This is the position in which the parts areshown in FIG. 3. At this time the drive through the high-speed drivemeans is interrupted and instead the drive takes place through thelow-speed drive means. In this way the speed of operation of the machineis reduced, for example, to the order of 600 rpm.

The left free end of the rock lever 150, as viewed in FIG. 6, extendsthrough a vertically extending slot 150 which is formed in the wall 96of the housing 94. At the exterior surface of the wall 96, the left freeend of the lever 150 is overlapped by the inner end of a swingableoperating finger 160 which is fixed intermediate its ends to a rotaryshaft 162 also supported for rotary movement by any suitable bearingsand extending parallel to the shaft 110 and through the wall 98 which isalso vertically slotted to provide for free swinging of the lever 150.The shaft 162 also fixedly carries a collar 164 to prevent axialdisplacement of the shaft 162. The right end of the shaft 162, as viewedin FIG. 6, extends through and beyond the intermediate wall 98 to theright side thereof. as viewed in FIG. 6,where this shaft 162 carriescontrol elements referred to in greater detail below,

The slot 08 through which the belt 86 extends is made wide enough toaccommodate an elongated rod 166 which is pivoted at its top end to endof the lever 160 which is distant from the rock lever 150. This rod 166extends freely through the slot 80 and is threaded at its bottom endinto the central threaded bore of a threaded closure plug 168 (FIG. 9)which closes the top end of a sleeve 170 whose bottom end is closed by asecond axially bored threaded closure plug 172. A rod 174 is slidablethrough the bore of the lower plug 172 and extends at its lower regionthrough the interior of a clamping sleeve 176 which is of an ellipticalconfiguration. As may be seen from FIGS. 1 and 2 this sleeve 176 alsoreceives in its interior the upper end of an elongated rod 178. Thebottom end of this rod is pivoted to the rearwardly directed ear 180 ofthe bar 82.

The portions of the rods 174 and 178 which overlap within the sleeve 176can be clamped together by way of a screw 182 threaded through a wall ofthe sleeve 176. In this way an adjustment of the total length of theassembly of the rods can be achieved.

As may be seen from FIG. 9, the upper end of the rod 174 is fixed to apiston 184 which slides within the hollow cylindrical sleeve 170. Belowthis piston a coil spring 186 is coiled around the part of the rod 174which is within the sleeve 170. A second coil spring 188 is compressedbetween the plug 168 and the piston 184. In this way the coil springs186 and 188 coact to provide longitudinal transmission of motion fromthe rod 174 to the rod 166, when the rod 174 is moved upwardly, with thespring 188 at this time providing a yieldability in this motiontransmission. On the other hand when the rod 174 is moved downwardly itis the spring 186 which tends to be compressed to provide a resilientlyyieldable transmission from the downwardly moving rod 174 to the sleeve170 and from the latter to the rod 166.

Thus, with this construction when the operator depresses the inner orrear edge 24 of the treadle 20, the rod 166 will be moved downwardly toswing the lever 160 and the shaft 162 therewith in a clockwisedirection, as viewed in FIG. 5, so that these components will now havethe position shown in FIG. 5 with the innerend of the finger which formslever 160 situated at an upper elevation enabling the spring to expandto the position shown in FIG. 6 so that the high-speed drive is engagedat this time and the operations proceed in the normal way. On the otherhand, when the front edge 26 of the treadle is depressed, the rod 166will be raised to locate the finger which forms the lever in theposition shown in FIG. 4, and now the end of the finger 160 distant fromthe rod 166 depresses the left free end of the rock lever 150, as viewedin FIG. 6, so that at this time the clutch 134 is engaged and the clutch104 is disengaged, and the parts have the position shown in FIGS. 3 and4 where the sewing operations are terminated. Therefore, the treadle 20and the connection between the latter and the lever 160 as well as thelever 150 form a means for switching over between the high-speed drivemeans and the low-speed drive means.

The intermediate wall 98 carries a pivot bolt 190 which serves topivotally support a block 192 which forms part of a blocking means ofthe invention. This block 192 carries a bolt around which one end of acoil spring 194 is hooked. The opposite end of this spring is joined bya screw 196 to the wall 126 of the housing 94. Thus the spring 194 urgesthe block 192 in clockwise direction about the pivot 190 as viewed inFIG. 4. The wall 90 fixedly carries a pin 198 which acts as a stop tolocate the block 192 in the position illustrated in FIG. 4.

At its top end the block 192 fixedly carries a relatively heavy coilspring 200 of relatively short length. When the block 192 engages thepin 198 the spring 200 is in the path of turning movement of thepositioning pin 138 fixed with a disc 136, so that during a rotation ofless than one revolution the pin 138 will engage the spring 200 and stopthe transmission to the needle 1 16. When the pin 138 engages the spring200 with the parts in the position of FIG. 4, the needle 116 isnecessarily located in the solid line position of FIG. 10 out of thework.

An elongated control finger 202 is bolted to the right side surface ofthe block 192 as viewed in FIGS. 4 and 5, and this finger 202 terminatesdistant from the block 192 in a tapered tip 204. This tip 204 is adaptedto coact with a tooth 206 of a swingable latch member 208 pivoted on thewall 98 by a pivot screw 210. A wire spring 212 is coiled about a screw214 carried by the wall 98 and is connected at one end to a pin carriedby the latch 208 so as to urge the latter in a counterclockwisedirection as viewed in FIGS. 4 and 5, around the pin 210.

The shaft 162 is fixed, as by a setscrew 216, with a control block 218which fixedly carries an elongated control finger 220. This controlfinger 220 extends beneath a perpendicular The parts may be assumed ashaving the rest positions shown in FIGS, 3 and 4. At this time the rod166 is in its upper position and the pin 220 is in the lower positionshown in FIG. 4. The spring 194 holds the block 192 against the pin 198and the positioning pin 138 is on top of the spring 200.

In order to start the operation the operator will depress the inner orrear edge 24 of the threadle so as to lower the rod 166 and swing thelever 160 into the position shown in FIG. 5. The result is that the pin220 engages and displaces the pin 222 so as to swing the block 192 inopposition to the spring 194 in a counterclockwise direction thusdisplacing the tapered tip 204 of the finger 202 above the latch tooth206 of the latch 208. Now this latter tooth 206 will coact with the tip204 of the finger 202 to prevent return of the block 192 to the positionshown in FIG. 4, so that the parts will remain operating. The upwardmovement of the end of the lever 160 distant from the rod 166 enablesthe left free end of the lever 150 as viewed in FIG. 6, to moveupwardly, so that the spring 140 can expand and engage the clutch 104 sothat the high-speed drive means operates the needle. At this time theclutch 134 is disengaged.

In this way the sewing operations will be carried out. When it isdesired to interrupt these operations the operator will depress theforward edge 26 of the treadle 20. The rod 166 will now return to theposition shown in FIG. 4. At the same time the pin 226 will turn in acounterclockwise direction, as viewed in FIG. 4, around the axis of theshaft 162, and the pin 226 will at this time engage the surface definingthe slot 224 in order to cam the catch 208 in a clockwise directionaround the pin 210 in opposition to the spring 212 so as to displace thelatch tooth 206 away from the tapered tip 204 of the finger 202 and thusrelease the block 192 to the spring 194 which now swings the block intoengagement with the pin 198 so as to locate the spring 200 in the pathof turning movement of the pin 138.

At the same time the end of the lever 160 distant from the rod 166 hasmoved down so as to swing the lever 150 in a counterclockwise directionabout the pin 152, as viewed in FIG. 6, thus causing the stud 148 toengage the clutch 134 while displacing the shaft 110 slightly to theleft, in opposition to the spring 140, so as to disengage the clutch104. In this way the drive has been switched over from the high-speeddrive means to the low-speed drive means and the pin 130 turns at thislower speed with the disc 136 until the pin 130 engages the spring 200so as to stop the needle 116 in the solid line position shown in FIG.10.

it will be recalled that during this time the lever 63 has beendisplaced between the solid and dot-dash line positions shown in FIG. 7while the swing lever has in both cases been turned in the samedirection so that the only difference is that when the lever 68 has thedot-dash line position of FIG. 7 the low-speed drive means is operativewhile when the lever 68 has the solid line position of FIG. 7 thehigh-speed drive means is operative. Upon release of the treadle thespring 42 will return the lever 30 to a position where the drive fromthe motor 28 to the pulley 40 is interrupted so that the machine drivewill stop.

Of course, the operator need only depress the edge 24 of the treadle 20in order to again resume the normal operations. Now the tip of thefinger 202 will again be displaced upwardly beyond the tooth 206 of thelatch 208, and even if the treadle is released without pushing down onthe edge 26, the tip of the finger 202 engage the tooth 206 to maintainthe parts operating at their normal speed which may, however. beincreased by further depression of the edge 24 so as to locate the pin220 in the position of FIG. 5, for example, where it coacts with the pin222 to locate the finger 202 upwardly beyond the latch 206.

As may be seen from FIGS. 3-6, the shaft 162 fixedly carries a radiallyextending lever 230 which is pivotally con nected at its upper free endto an elongated rod 232 which extends through an opening of the wall 126out to the exterior of the housing 94. At its exterior end portion therod 232 carries locknuts 234 which engage one end of the spring 236coiled around the rod 232 and pressing against the exterior surface ofthe wall 126. Thus the spring 236 acts through the linkage 232, 230 tourge the shaft 162 to turn in a counterclockwise direction, as viewed inFIGS. 4 and 5. This construction serves to balance to some extent theweight of the treadle so that it is easier to swing the treadle 20.

As is particularly apparent from FIG. 2, the housing 94 and all of thestructure carried thereby forms a unit which can be independentlymounted on the table 16 at a position with respect to the sewing headwhich will enable the belt 112 to extend around a toothed pulley fixedto the drive shaft of the sewing head. Of course, the rod 166 will beseparately fastened to the lever which form part of the unit carried bythe housing 94. In this simple way the entire structure of the inventioncan readily be attached to an existing sewing machine.

Among the advantages of the structure of the invention are not only thesimplicity of the structure and the reliability of the operationthereof, as well as the ease with which the structure is assembled withan existing machine, but in addition the termination of the operationswill necessarily take place only when the lower-speed drive means isoperating so that when the blocking means formed by the block 192 andspring 200 becomes situated in the path of movement of the positioningpin 138, this latter pin is necessarily turning at a relatively slowspeed so as to engage the spring 200 to bring the parts to a stop in arelatively smooth, impact-free manner positioning the needle 116 out ofthe work and at the same time eliminating any sudden stressing of thecomponents.

Iclaim:

1. In a machine which has a working element which is to be located in agiven position when it does not operate, highspeed drive means fortransmitting a relatively high-speed drive to the working element duringnormal operation of the machine, low-speed drive means for transmittinga drive of a lower speed to the working element only in preparation forstopping the operation thereof, means coacting with both of said drivemeans for switching over from said high-speed to said low-speed drivemeans preparatory to stopping the operation of said working element,each of said drive means having an operating and a nonoperatingposition, said low-speed drive means automatically assuming itsoperating position in response to changing of said high-speed drivemeans from its operating to its nonoperating position and saidhigh-speed drive means automatically assuming its operating position inresponse to changing of said low-speed drive means from its operating toits nonoperating position, so that at any given moment one of said drivemeans is in its operating position, and blocking means coacting withsaid low-speed drive means for blocking, whenever said low-speed drivemeans assumes its operating position, the transmission of a drive fromthe latter to the working element when the working element has beenlocated in said given position by said low-speed drive means, the latterdrive means thus operating only during stopping of the working elementto drive the latter at said lower speed until said blocking means blocksthe transmission of the drive from said low-speed drive means to saidworking element, said high and low speed drive means both having acommon input transmission component and a common output transmissioncomponent.

2. The combination of claim 1 and wherein said high-speed drive meanshas a direct transmission between said common input and outputtransmission components and said low-speed drive means has a stepdowntransmission between said input and output components.

3. The combination of claim 2 and wherein said stepdown transmission ofsaid low-speed drive means includes a slip clutch and a driven elementdriven thereby, said blocking means being positioned in the path ofmovement of said driven element to stop the movement thereof when saidworking element reaches said given position and said slip clutchslipping when said driven element engages said blocking means.

4. The combination of claim 3 and wherein a high-speed slip clutch formsthe direct transmission between the input and output transmissioncomponents.

5. The combination of claim 3 and wherein a means for switching fromsaid low-speed to said high-speed drive means acts on said blockingmeans to displace the latter away from said driven element to releasethe drive to said working element.

6. The combination of claim 5 and wherein a catch means coacts with saidblocking means for preventing return of the latter to a position whereit is located in the path movement of said driven element.

7. The combination of claim 6 and wherein a spring means urges saidblocking means to said position in the path of movement of said drivenelement and the means for switching from said high-speed to saidlow-speed drive means coacting with said catch means to release thelatter so as to release said blocking means to said spring means to bedisplaced thereby to said blocking position.

8. The combination of claim 1 and wherein a driving motor is operativelyconnected with said common input component for driving the latter, andoperator-actuated means coacting with said driving motor for releasingthe latter for operation both when operating through said high-speeddrive means and when operating through said low-speed drive means.

9. The combination of claim 8 and wherein said working element is aneedle of a sewing machine, said operator-actuated control meansincluding a swing-lever having a neutral rest position when a drive isnot transmitted from said driving motor to said common input component,a treadle, and a linkage means interconnecting said treadle with saidswing lever for swinging the latter in the same direction when thetreadle is turned in one direction to actuate the high-speed drive meansand when said treadle is turned in an opposite direction to actuate thelow-speed drive means.

10. The combination of claim 8 and wherein the means for switchingbetween said high-speed and low speed drive means includes an elongatedswitching component operatively con nected with said treadle to move inone direction when said treadle is turned in one direction and to movein an opposite direction when said treadle is turned in the oppositedirection.

11. The combination of claim 1 and wherein said working element is asewing machine needle, an operating head assembly connected to theneedle for operating the latter, said highand low-speed drive meanstogether with said blocking means forming part of a unit separate fromsaid operating head, and transmission means transmitting the drive fromsaid unit to said operating head so that said unit can be separatelyassembled with a sewing machine.

1. In a machine which has a working element which is to be located in agiven position when it does not operate, high-speed drive means fortransmitting a relatively high-speed drive to the working element duringnormal operation of the machine, low-speed drive means for transmittinga drive of a lower speed to the working element only in preparation forstopping the operation thereof, means coacting with both of said drivemeans for switching over from said high-speed to said low-speed drivemeans preparatory to stopping the operation of said working element,each of said drive means having an operating and a nonoperatingposition, said low-speed drive means automatically assuming itsoperating position in response to changing of said high-speed drivemeans from its operating to its nonoperating position and saidhigh-speed drive means automatically assuming its operating position inresponse to changing of said low-speed drive means from its operating toits nonoperating position, so that at any given moment one of said drivemeans is in its operating position, and blocking means coacting withsaid low-speed drive means for blocking, whenever said low-speed drivemeans assumes its operating position, the transmission of a drive fromthe latter to the working element when the working element has beenlocated in said given position by said low-speed drive means, the latterdrive means thus operating only during stopping of the working elementto drive the latter at said lower speed until said blocking means blocksthe transmission of the drive from said low-speed drive means to saidworking element, said high and low speed drive means both having acommon input transmission component and a common output transmissioncomponent.
 2. The combination of claim 1 and wherein said high-speeddrive means has a direct transmission between said common input andoutput transmission components and said low-speed drive means has astepdown transmission between said input and output components.
 3. Thecombination of claim 2 and wherein said stepdown transmission of saidlow-speed drive means includes a slip clutch and a driven element driventhereby, said blocking means being positioned in the path of movement ofsaid driven element to stop the movement thereof when said workingelement reaches said given position and said slip clutch slipping whensaid driven element engages said blocking means.
 4. The combination ofclaim 3 and wherein a high-speed slip clutch forms the directtransmission between the input and output transmission components. 5.The combination of claim 3 and wherein a means for switching from saidlow-speed to said high-speed drive means acts on said blocking means todisplace the latter away from said driven element to release the driveto said working element.
 6. The combination of claim 5 and wherein acatch means coacts with said blocking means for pReventing return of thelatter to a position where it is located in the path movement of saiddriven element.
 7. The combination of claim 6 and wherein a spring meansurges said blocking means to said position in the path of movement ofsaid driven element and the means for switching from said high-speed tosaid low-speed drive means coacting with said catch means to release thelatter so as to release said blocking means to said spring means to bedisplaced thereby to said blocking position.
 8. The combination of claim1 and wherein a driving motor is operatively connected with said commoninput component for driving the latter, and operator-actuated meanscoacting with said driving motor for releasing the latter for operationboth when operating through said high-speed drive means and whenoperating through said low-speed drive means.
 9. The combination ofclaim 8 and wherein said working element is a needle of a sewingmachine, said operator-actuated control means including a swing-leverhaving a neutral rest position when a drive is not transmitted from saiddriving motor to said common input component, a treadle, and a linkagemeans interconnecting said treadle with said swing lever for swingingthe latter in the same direction when the treadle is turned in onedirection to actuate the high-speed drive means and when said treadle isturned in an opposite direction to actuate the low-speed drive means.10. The combination of claim 8 and wherein the means for switchingbetween said high-speed and low-speed drive means includes an elongatedswitching component operatively connected with said treadle to move inone direction when said treadle is turned in one direction and to movein an opposite direction when said treadle is turned in the oppositedirection.
 11. The combination of claim 1 and wherein said workingelement is a sewing machine needle, an operating head assembly connectedto the needle for operating the latter, said high- and low-speed drivemeans together with said blocking means forming part of a unit separatefrom said operating head, and transmission means transmitting the drivefrom said unit to said operating head so that said unit can beseparately assembled with a sewing machine.